User`s manual

SGC SG-500 SmartPowerCube™ User’s Manual, Page 10
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e. Now switch the transceiver to SSB, and transmit in a normal voice. The ATTEN circuit should
not activate, except on occasional voice peaks. (This concludes the test transmission. You can
now connect your station antenna and any other interconnections.)
INPUT DRIVE LEVELS: The amplifier reduces power when the ATTEN circuit activates, and then
must be driven through a higher input range to derive maximum output. Some 100-watt class amateur
transceivers may not be capable of producing sufficient output levels to drive the SG-500 for maximum
output. Therefore, as stated before, we recommend using the low input range (10-50 Watts) for normal
operation.
7.2 PTT KEYING: AUTO vs. MANUAL
The amplifier can be keyed either manually or automatically – the best method will depend on your
preference or application. Please note that whenever either PTT or Filter switches are changed, you must
turn the power off and back on to acknowledge the change.
Manual Keying – This requires a wire connection to your transceiver; the PTT line (on the ACCESS
connector) needs to be pulled low (to ground) when your transceiver is keyed to transmit. This is the
preferred configuration to be used. Check with the documentation provided with your particular
transceiver for details on where to access this connection.
Note: In manual PTT and Auto Filter mode, there will be a 10-15 msec delay while the CPU
measures the frequency and selects the correct filter band.
Automatic Keying – This uses RF sensing to detect when you transmit, and then brings the amplifier on-
line. Although automatic keying requires no control line, a small associated delay may be encountered in
SSB mode due to the “rise time” characteristic of SSB modulation.
7.3 Mobile Installation of the SG-500
If you are operating the amplifier mobile, please remember that the minimum size wire to be used from
the battery to the amplifier is AWG #6. Heavier wire is preferred. The recommended way to install the
amplifier in mobile installations is to install a second battery next to the amplifier.
Operating HF mobile at the 500 watt level requires careful planning and understanding of RF and
automotive systems. The information needed regarding this is too expansive to be adequately dealt with
here in this manual.
In response to customer inquiries, and from invaluable knowledge gained in this area by SGC research
staff, SGC offers a highly informative publication called “Go Mobile at 500 Watts” which outlines the
complete installation process in a variety of vehicles. This book is available for free download from our
website at www.sgcworld.com.
7.4 SG-500 and SG-235 Interconnections
When the SG-500 is used with the SG-235 Smartuner™, they form the heart of an outstanding 500 watt
automatically tuned HF system. Interconnections between the SG-500 and SG-235 permit amplifier
keying only when a proper antenna impedance match has been found. Only a few connections need to be